Embolic stroke of undetermined source correlates to atrial fibrosis without atrial fibrillation

Abstract

ObjectiveTo examine the hypothesis that atrial fibrosis and associated atrial cardiopathy may be in the causal pathway of cardioembolic stroke independently of atrial fibrillation (AF) by comparing atrial fibrosis burden between patients with embolic stroke of undetermined source (ESUS), patients with AF, and healthy controls.MethodsWe used late-gadolinium-enhancement MRI to compare atrial fibrosis in 10 patients with ESUS against 10 controls (no stroke, no AF) and 10 patients with AF. Fibrosis was compared between groups, controlling for stroke risk factors.ResultsMean age was 51 ± 15 years, and 43% of participants were female. Patients with ESUS had more atrial fibrosis than controls (16.8 ± 5.7% vs 10.6 ± 5.7%, p = 0.019) and similar fibrosis compared to patients with AF (17.8 ± 4.8%, p = 0.65). Odds ratios of ESUS per quartile of fibrosis were 3.22 (95% CI [CI] 1.11–9.32, p = 0.031, unadjusted) and 3.17 (95% CI 1.05–9.52, p = 0.041, CHA2DVASc score adjusted). Patients with >12% fibrosis had a higher percentage of ESUS (77.8% vs 27.3%, p = 0.02), and patients with >20% fibrosis had the highest proportion of ESUS (4 of 5).ConclusionsPatients with ESUS exhibit similar atrial fibrosis compared to patients with AF and more fibrosis than healthy controls. Fibrosis is associated with ESUS after controlling for stroke risk factors, supporting the hypothesis that fibrosis is in the causal pathway of cardioembolic stroke independently of AF. Prospective studies are needed to assess the role of anticoagulation in primary and secondary stroke prevention in patients with high atrial fibrosis.

Left Atrial Volume Index Predicts New-Onset Atrial Fibrillation and Stroke Recurrence in Patients with Embolic Stroke of Undetermined Source

“…Consideration should be given to measurement of atrial volume over unidimensional atrial measurements in case selection for randomized controlled trials investigating anticoagulation strategies for ESUS. Cardiac MRI may offer better resolution in detailing LA morphology, and further research using such imaging modalities is needed to elucidate the relationship between LA cardiopathy and stroke [19].…”

Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source during 3 Years of Prolonged Monitoring with an Implantable Loop Recorder

“…Instead, we assessed the proportion of ESUS patients with AF documentation if ECG monitoring is maximized and extended it to a period of 3 years. Other potential causes are cardiac diseases of the left ventricle, 14 , a PFO 15 , as well as rare causes such as coagulation disorders or an underlying malignancy 12 . To dissect and to attribute such potential causes in ESUS patients, additional prospective studies are important including detailed carotid plaque imaging, cardiac imaging and laboratory studies together with long-term ECG monitoring.…”

Left Atrial Structural Remodelling in Non-Valvular Atrial Fibrillation: What Have We Learnt from CMR?

“…The extension of baseline LA fibrosis also means higher thromboembolic risk [4,9,34] and subsequently, higher risk for developing major adverse cardio-and cerebrovascular events (MACCE) [35]. In a study conducted by King et al, baseline LA fibrosis reported as Utah stages correlated with both thromboembolic risk scores CHADS2 and CHA2DS2-VASc [35].…”

“…The different types of atrial remodelling are interconnected, as structural remodelling leads to LA dysfunction and subsequent electrical changes in the cardiomyocytes [2]. Fibrosis is the hallmark of LA structural remodelling and is associated with increased risk of stroke, heart failure (HF) development and/or progression and poorer catheter ablation (CA) outcomes with increased recurrence rates [3,4]. Subsequently, imaging structural remodelling is necessary given its impact on CA candidate selection, technique and post-procedural outcomes and prognosis.…”